On Block Noncoherent Communication with Low-Precision Phase Quantization at the Receiver

TL;DR

This paper analyzes the capacity of block noncoherent AWGN channels with low-precision phase quantization at the receiver, demonstrating that a small number of phase bins can recover most of the unquantized capacity.

Contribution

It introduces a receiver architecture with phase-only quantization and provides a low complexity method to compute channel capacity, highlighting its effectiveness for low-precision ADCs.

Findings

8-bin phase quantization recovers over 80-85% of unquantized capacity

12-bin phase quantization recovers over 90-95% of unquantized capacity

Dithering improves performance under severe quantization

Abstract

We consider communication over the block noncoherent AWGN channel with low-precision Analog-to-Digital Converters (ADCs) at the receiver. For standard uniform Phase Shift Keying (PSK) modulation, we investigate the performance of a receiver architecture that quantizes only the phase of the received signal; this has the advantage of being implementable without automatic gain control, using multiple 1-bit ADCs preceded by analog multipliers. We study the structure of the transition density of the resulting channel model. Several results, based on the symmetry inherent in the channel, are provided to characterize this transition density. A low complexity procedure for computing the channel capacity is obtained using these results. Numerical capacity computations for QPSK show that 8-bin phase quantization of the received signal recovers more than 80-85 % of the capacity attained with unquantized observations, while 12-bin phase quantization recovers above 90-95 % of the unquantized capacity. Dithering the constellation is shown to improve the performance in the face of drastic quantization.